Abstract: A method of estimating the airflow into a compression ignition engine having an exhaust gas recirculation system (EGR) and a variable geometry turbocharger (VGT). The method includes the steps of generating an EGR flow value as a function of the intake manifold pressure (MAP), exhaust manifold pressure (EXMP), position of the exhaust gas recirculation valve, and temperature of the gas flowing through the EGR. From this calculation, the method generates an intake airflow value (MAF) as a function of the EGR flow value and the intake aircharge temperature. The intake airflow value is used, in turn, to control the position of the EGR valve. The disclosed method thereby eliminates the necessity for a MAF sensor.

Abstract: An Electronic Engine Controller (EEC) which controls operation of an engine employs a switching type oxygen sensor to determine the composition of exhaust gas produced by the engine. The EEC enhances the signal received from the oxygen sensor to generate quantitative information from the qualitative information received from the oxygen sensor. The EEC utilizes the enhanced information from the oxygen sensor to adapt Transient Fuel Control (TFC) parameters. The EEC detects a transient, quantifies the transient in terms of two TFC parameters and adapts the TFC parameter employing fuzzy-logic controls.